In a railway vehicle like a Shinkansen bullet train, during running, in association with the imposition of various types of vibration acceleration such as swaying and rolling, a vibration in a lateral direction is generated. Since the vibration deteriorates riding comfort, a vibration suppression device is mounted in a general railway vehicle, so that an air cushion, a coil spring, a damper, and/or the like are disposed between a vehicle body and a bogie truck to absorb the impact that the vehicle body receives from the bogie truck, and an actuator capable of extending and retracting in a lateral direction is disposed to attenuate the vibration of the vehicle body.
As the actuator, a fluid pressure type actuator with pneumatic pressure or hydraulic pressure as a drive source, an electric actuator with electric power as a drive source, and the like are adopted. In the actuator, a main body is coupled to any one of the bogie truck side and the vehicle body side, and a movable rod is coupled to the other side. By detecting the acceleration acting on the vehicle body in a lateral direction by an acceleration sensor and by extending and retracting a rod in association with the detected acceleration, the actuator causes the vehicle body to vibrate and at the same time, adjusts a damping force of the actuator to attenuate the vibration.
When the railway vehicle runs in a curve section, not only a vibrational component for generating the vibration in the vehicle body but also a steady-state component steadily acting on the vehicle body attributable to a centrifugal force is superimposed on the acceleration detected by the acceleration sensor. Thus, when extension/retraction motion of the actuator is controlled based on only an output from the acceleration sensor, there is a risk that the vibration of the vehicle body cannot effectively be suppressed.
As a technique for solving this problem in the background art, for example, PATENT LITERATURE 1 discloses a vibrational component acceleration estimation device and a vibrational component acceleration estimation method for, with a damper capable of changing a damping force for suppressing a vibration of a vehicle body being adopted, estimating the acceleration of a vibrational component acting on the vehicle body in order to perform skyhook semi-active control to the damper when a railway vehicle runs in a curve section.
The estimation device disclosed in PATENT LITERATURE 1 includes a detection means for detecting the acceleration acting on the vehicle body in a lateral direction, a theoretical excess centrifugal acceleration calculation means for determining a theoretical excess centrifugal acceleration αL acting on the vehicle body in a lateral direction based on track information at a running point of the railway vehicle and a running speed of the railway vehicle, and a vibration acceleration calculation means for determining the acceleration of the vibrational component acting on the vehicle body based on the acceleration detected by the detection means and the theoretical excess centrifugal acceleration αL determined by the theoretical excess centrifugal acceleration calculation means. In the estimation device and the estimation method disclosed in PATENT LITERATURE 1, determining the theoretical excess centrifugal acceleration αL is differently performed between the case where the railway vehicle is provided with a vehicle body tilting mechanism having a vehicle body tilting device for tilting the vehicle body relative to a bogie truck and the case where the railway vehicle is a non-tilting vehicle having no vehicle body tilting device, and the following Equation (a) or (b) is used.
In a case with the vehicle body tilting mechanism:αL=D×(V2/R−g×C/G×β−g×θ)   (a)
in a case of the vehicle body free of tilting function:αL=D×(V2/R−g×C/G×β)   (b)
wherein in the above Equations (a) and (b), D represents a positive or negative sign showing the direction of curvature, V denotes a running speed, R denotes a curvature radius of the track, g denotes gravitational acceleration, C denotes a cant amount of the track, G denotes a track gauge, β denotes a curve coefficient, and θ denotes a tilting angle of the vehicle body relative to the bogie truck.